Prof. Barnard on a modification of the Ericsson Engine. 237 
CC, Working we dad P’P’, Condensing cago Surface. 
0’C’, Conden Eo Supply Pisto 
CHCHS cay et , Reservoir. 
,V’, V"’, &e, Valves. F, Furnace. 
R’, Regenerator, O, Hot Air Chamber, 
PPP, Working Piston Surface. 
A reference to the accompanying diagram will explain what is 
meant. Let CC be the working cylinder, C’OQ’ a second cylin- 
der, corresponding to Ericsson’s supply cylinder, but which will 
here be called the condensing cylinder, and C’C” a third, which 
may be called the proper supply cylinder of this proposed engine. 
Let P be the working surface of the large piston, P’ the c 
densing iit of the same piston, and P” the supply piston.* 
€ air is proposed to be admitted through valves on the top 
of C’C’ into that cyli nder, it is to be driven from that cylinder 
into C’C”, through valves in the bottom of it, this cylinder hav- 
* To avoid giving the pile of cylinders too great altitude, it is proposed to sink 
the condensing cyl nee: bergen i binary the working cylinder. For this purpose 
e 
as in Eriesson’s stationary single aie, instead of being placed between the sup- 
Py and working cylinder, as in the ship. 
t will be observed, pars closing the top of the cylinder C’’C’’, and os 
Valves in P’’, we may, if we please, cause the communication — the reservoir to 
be made at the top of the scsi ue at ere — ot rare oes 
th ‘wriig beuattse tg ve space rtiteho woul 
be ni varinen, beam to — hat higher, w' a ship, may be a 
